1. Field of the Invention
The present invention is related to the field of network telephony, and more specifically to clusters of devices, softwares and methods for improved handling of a gatekeeper load in VoIP communication.
2. Description of the Related Art
Networks such as the internet or Local Area Networks (LANs) are increasingly used for telephony. Voice data is transmitted through a network as packets. When a voice call is originated using the traditional telephone technology (circuit switching), the voice data is converted to such packets by a network device called a gateway. Such gateways are considered to be endpoints of the network in question.
The packets travel through the network using a suitable Voice over Internet Protocol (VoIP). A superior VoIP protocol has proven to be the H.323 standard, which is a short notation for Recommendation H.323 of the International Telecommunications Union (ITU).
Referring now to FIG. 1, an operating unit of the H.323 standard is described in more detail. The operating unit is a logical zone, which is also known as a H.323 zone. The shown H.323 zone includes a gatekeeper 114, and endpoint devices 122, 124, 126, 128 coupled with gatekeeper 114.
In the example of FIG. 1, endpoint devices 122, 124, 126, 128 are Gateway-X 122, Gateway-Y 124, Gateway-Z 126, and VoIP telephone 128. Gateway-X 122, Gateway-Y 124, Gateway-Z 126 are H.323 gateways. In general a H.323 gateway is an endpoint on the H.323zone which provides real-time, two-way communications between H.323 terminals on the H.323 zone and other ITU-T terminals in a network, or to another H.323 gateway. A H.323 gateway is specified in more detail in section 6.3 of the H.323 Standard Version 4, approved 11/2000.
The H.323 standard defines the relationship between gatekeeper 114 and endpoint devices 122, 124, 126, 128. Gatekeeper 114 exchanges signals with endpoint devices 122, 124, 126, 128 according to a protocol such as RAS (Registration Admission and Status). A H.323 gatekeeper is specified in more detail in section 6.4 of the H.323 standard draft Version 4, approved 11/2000.
More particularly, gatekeeper 114 provides address translation and controls access to the network for endpoint devices 122, 124, 126, 128. Gatekeeper 114 maintains a registry of endpoint devices 122, 124, 126, 128. Endpoint devices 122, 124, 126, 128 register with gatekeeper 114 at startup, and request admission to a call from gatekeeper 114. Gatekeeper 114 can provide additional services to endpoint devices 122, 124, 126, 128, such as bandwidth management, and locating other terminals and gateways. These services are typically provided by RAS signals.
Gatekeepers, such as gatekeeper 114, are typically made from generic, multi-purpose platforms. This is because of cost considerations, and also to accommodate the recently accomplished scalability of the H.323 Standard.
When a gatekeeper fails, its associated endpoint devices become disconnected. In other words, when gatekeeper 114 fails, endpoint devices 122, 124, 126, 128 effectively fail, even though individually they may still be functioning properly.
A problem has been that the generic, multi-purpose platforms that are typically made for asynchronous IP networks do not necessarily support well the synchronous voice communication required by VoIP protocols. Accordingly, gatekeepers in the prior art tend to fail at the rate of other IP devices. Used in network telephony, however, these failures are noticed by live users. Such prevents network telephony from being accepted as a viable alternative to circuit switched telephony.